Internal Pressure Relief Valve Modification

Issue

Suppressing Chiller Noise and Operating at Recommended Flow Rate

 

Environment

• ThermoFlex 900
• ThermoFlex 2500

Resolution

Pressure Relief Valve (Disassembled)

Please follow the procedure linked here to  remove and disassemble the valve: Internal Pressure Relief Valve Removal

Forming a Sleeve

The sleeve material should not exceed 0.35 mm due to limited clearance within the valve body.

Avery Style Edge Insertable Plastic Dividers were found to be an inexpensive, locally sourced option for sleeve material.

1. Cut out a 42 x 51 mm rectangle of sleeve material. This size will ensure that the spring is full insulated.  

Note: Compensation for spring compression is not required for iCAP PRO systems.  The valve will be fully open to meet water flow requirements.

2. Wrap the spring with the insulating sleeve and reassemble the valve.

 

3. Check system water flow (using Service Software for iCAP PRO or Instrument Control for iCAP Qnova Series) and adjust flow as necessary.

 

An alternate solution is as follows:

Wrap a heat shrink around the spring located inside of the pressure-regulating valve- the heat shrink must have a width of 25 mm to accommodate for the spring's 17 mm diameter. You will also have to equip yourself with a heat gun, if you don't already have one. I have attached a picture of the spring wrapped in a heat shrink.

 

Analysis

Excessive chiller noise is originating from the pressure relief valve, located on the top  le rear of the chiller.  

Investigation has shown that an internal spring is vibrating on the valve body.

Fashioning a sleeve around the spring dampens the vibration and provides for quiet operation at desired flow rates/pressures.